Intelligent Speed Adaptation (ISA) systems hold great promise for improving roadway safety by reducing instances of speeding. However, previous evaluations of these systems have revealed a significant paradox. Mandatory systems that strictly enforce speed limits, while effective, face significant consumer acceptance hurdles. Moreover, young male drivers, who would benefit the most from ISA, tend to be the most negatively disposed towards these systems. Voluntary and advisory systems, on the other hand, are more acceptable to drivers. However, these systems are significantly less effective in reducing speeding. In addition to the tradeoff between effectiveness and acceptability, there is also significant concern that ISA systems may, in fact, have an adverse affect on roadway safety. This paper reviews the research that has been conducted on ISA, and presents possible strategies to maximize both effectiveness and acceptability and mitigate deleterious effects on roadway safety.